Propagate InstructionSetFeatures to ElfBuilder.

This is subset of CL171665 and it separates it into two.
It will be needed to generate .MIPS.abiflags ELF section.

Change-Id: I5557e7cb98d0fa1dc57c85cf6161e119c6d50a1a
diff --git a/compiler/debug/dwarf/dwarf_test.h b/compiler/debug/dwarf/dwarf_test.h
index 41bfe79..e2f0a65 100644
--- a/compiler/debug/dwarf/dwarf_test.h
+++ b/compiler/debug/dwarf/dwarf_test.h
@@ -62,7 +62,7 @@
     InstructionSet isa = (sizeof(typename ElfTypes::Addr) == 8) ? kX86_64 : kX86;
     ScratchFile file;
     FileOutputStream output_stream(file.GetFile());
-    ElfBuilder<ElfTypes> builder(isa, &output_stream);
+    ElfBuilder<ElfTypes> builder(isa, nullptr, &output_stream);
     builder.Start();
     if (!debug_info_data_.empty()) {
       builder.WriteSection(".debug_info", &debug_info_data_);